A newly discovered class of nanoscale materials, the metal-carbon nanoencapsulates, has considerable potential to improve on current molecular-based MRI contrast enhancing agents. Metal-carbon nanoencapsulates are 2 nm diameter and larger particles in which graphitic carbon layers encase single crystals of metals or metal carbides. Their continuous graphitic carbon shells are several layers thick and highly stable. This shell protects the metal nanocrystal from oxygen and water, prevents the metal from leaving the encapsulate, allows magnetic interactions between the metal and exterior molecules, and provides a scaffolding for chemical derivitization. These physical characteristics impart significant advantages to metal-carbon nanoencapsulates and will result in a safer, more effective class of novel MRI contrast enhancing agents based on metal-carbon nanoencapsulates. The nanoencapsulates will be aminated, allowing for solubilization and coupling reactions on the surface of the nanoencapsulate. The relaxivity characterisitics of gadolinium containing solubilized nanoencapsulates with be evaluated, and the covalent conjugation of proteins will be tested. Potential applications for these nanoencapsulate contrast agents include imaging of the blood pool, RES, cancerous lesions, and targeted imaging of receptors and gene expression. PROPOSED COMMERCIAL APPLICATION: The development of a new class of potent MRI contrast enhancing agents based on magnetic metal-carbon nanoencapsulates with higher stabilities, higher relaxivities, lower required in vivo concentrations and novel utility in target-specific imaging applications will have substantial commercial impact. Once fully developed, these safer and more powerful contrast enhancing agents will be in demand for clinical use in MRI laboratories and hospitals around the country in applications like MR angiography, imaging of reticuloendothelial system components, imaging of cancerous lesions with targeted agents, and for imaging gene expression and other receptors.